Method for measuring calcium constituent in silicon aluminum calcium barium alloy

Abstract

The invention discloses a method used for measuring the calcium element in a silicon, aluminum, calcium and barium alloy, which comprises the following steps: a test sample is placed in a beaker, and deionized water is added until the test sample is wet; 9.5 to 10.5 millimeter of nitric acid is added; 1 to 2 millimeter of hydrofluoric acid is titrated; the mixture solution is heated until completely dissolved; perchloric acid is added; the mixture solution is heated until the sample volume is reduced to 1 to 2 millimeter; the mixture solution is naturally cooled; the perchloric acid is further added, and the mixture solution is heated until the sample volume is reduced to 1 to 2 millimeter; the hydrochloric acid and the deionized water are further added; the mixture solution is heated until all salts are dissolved, and the mixture solution is naturally cooled until the temperature is lower than 40 DEG C; the test sample is placed into a volumetric flask with scales and diluted with the deionized water; a mother solution is placed into a trigonal cup, the deionized water, trolamine (1 added by 1), lemery, bitter salt and an calcon-carboxylic acid are added, and the mother solution is adjusted to be red with potassium hydroxide; the potassium hydroxide is further added; EDTA is titrated until an end point that the mother solution becomes blue; and an analyzing result is computed. The method does not need precipitation separation and filtration, and has the acute end point without intermediate color and improved measuring accuracy.

Description

Technical field [0001] The invention relates to the field of analytical chemistry, and belongs to an analytical method for determining calcium in a silicon-aluminum-calcium-barium alloy by adopting an EDTA direct titration method. Background technique [0002] At present, the detection methods of calcium in silicon-aluminum-calcium-barium alloys generally use ammonia to separate iron and aluminum, ammonium persulfate to separate manganese, potassium sulfate to precipitate barium, calcium indicator as indicator, EDTA titration. This method is cumbersome to operate, has a long analysis cycle and high cost. [0003] In order to improve the efficiency of analysis and testing, people have done a lot of work around the element analysis of silicon-aluminum-calcium-barium alloys and have achieved certain results, such as the "Silicon-aluminum-Calcium-Barium Alloy In the article "Determination of Medium Barium and Calcium", it is disclosed that the content of barium and calcium can be mea...

AI Technical Summary

Problems solved by technology

After analysis, although this method can measure the content of barium and calcium at the same time, its disadvantages are: the first is that the calcium in the solution is not fully released due to the one-time addition of 20 ml of perchloric acid; the second is that the discoloration reaction at the end of the solution is slow , there is a transitional color; the third is that the pH value of the solution is unstable due to the one-time addition of 20 milliliters of potassium hydroxide, and the reproducibility is poor; the fourth is that the environment is polluted due to the addition of more hydrofluoric acid; five. is required to filter

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